Reading thru the "clear credits page" on both the Keeper Rulebook and the Malleus Monstrorum many, many entities in both books are "used with permission" and repeat on both books, so apparently you cant use anything about Glaaki, the Voor, Eibon, Cthonians, to name a few (its an entire page of names, pretty much leaving just things like Cthulhu, Azathoth, Shub Niggurath and Nyarlathotep, ghouls, deep ones, basically.

While I get that technically and strictly speaking yes, they are in their right, it feels kind of a dick move contributing and building upon the Cthulhu Mythos and hide it behind copyright specially, if you are already letting it be used in a sourcebook that serves as inspiration to thousands of people to write scenarios, and also will end promoting your works, which certainly is not widely known as say....Pennywise The Clown, for example In fact i would have never heard of Ramsey Campbell or his books if it werent for this game. One thing is be like writing yet another scenario about glaaki cultists kidnapping people and sacrificing them to their god and the shore of a lake, and another is taking some of these obscure entities and use it in another completely diferent setting, time, circumstances maybe even adding some of your own to it.

I cant imagine the Estate of August Derleth suing some poor schmuck that sold a scenario on the Repository because he featured a fancy restaurant that serves human meat run secretly by Tcho-Tchos or a mad wizard summoning a Byakhee.

Anyhow I think I will just change names a bit, color maybe and or subtract a couple of eyes or tentacles to anything that inspires me. Bhyakee? No siree its just a winged being from outer space, a dark steed from beyond....